lilac

You can try using the process of elimination. There are five main reasons that lilacs fail to bloom: insufficient sunlight, too much nitrogen fertilizer, improper planting (planted too deeply), improper pruning (pruning at the wrong time) or winterkill of the flower buds. If you are fertilizing your bushes (or near your bushes), stop. Lilacs set their flower buds for next year on this year's growth. If you pruned them last season in late summer-say late July or August-you may have removed the flower buds for this growing season. Also, lilacs will typically not bloom the season after a harsh pruning, so you may need to wait until next year before you see flowers. If you suspect winter damage to your flower buds, you can only hope for milder winters or plant a hardier variety. Pulling some soil back from the roots will help if you think it may be planted too deeply. Lilacs need full sun to flower. You might take a sucker from your lilac bush and try growing it in a new location.

I think it must be sun i have not pruned it .Do you think i could dig it up and put it in a sunny spot if i can when is the best time.And thank you for answering last ?.